Lithospheric bulges recorded by regional unconformities. The case of mesozoic-tertiary apulia

Abstract

Cyclic shallow-water carbonate sequences in the Cretaceous of Southern Italy are punctuated by regional unconformities associated with bauxites and palaeokarst features. Direct and indirect evidence strongly suggests that, despite their apparent plate interior position, tectonics rather than eustasy was responsible for subaerial exposure, long enough to form bauxites. In-plane stress-related lithospheric arching caused by orogenic deformation along the distant active margins of Apulia is invoked to explain the vertical stacking of a series of regional unconformities (one of them marked by bauxites) on land and under the sea. The case history of Apulian bauxites associated with a Turonian arching allows a first estimate of the duration of a stress-related ‘distant’ perturbation of a subsiding passive continental margin.